Good morning. This is Eric Knoff with the Gallatin National Forest Avalanche Advisory issued on Sunday, February 15, at 7:30 a.m. Montana Ale Works in partnership with the Friends of the Avalanche Center sponsors today’s advisory. This advisory does not apply to operating ski areas. The GNFAC would like to extend a huge thanks to all who participated in the King and Queen of the Ridge yesterday. This fundraising event was a huge success with over forty hikers rallying in support of avalanche education.
Overnight the northern Gallatin Range picked up 1” of new snow while the rest of the advisory area remained dry. This morning, mountain temperatures are actually below freezing and range from the upper teens to mid-20s F under partly to mostly cloudy skies. Winds are blowing 10-20 mph out of the W-NW. Today, skies will remain partly to mostly cloudy and temperatures will warm into the upper 20s to low 30s F. Winds will continue to blow 10-20 mph out of the W-NW. No accumulating snowfall is expected over the course of the day. There is a better chance of precipitation tonight and tomorrow. The mountains should receive 1-3” of snow by tomorrow afternoon.
Southern Madison Range Southern Gallatin Range
Lionhead Area near West Yellowstone
Yesterday - abundant sunshine, calm winds and temperatures in the 40s F softened all but north facing slopes. As a result, the snow surface will be locked up with a firm ice crust on solar aspects today. This will help stability on most slopes, but will make for some hideous riding conditions.
North facing slopes still hold soft-powdery snow but these are also the areas that most likely harbor buried surface hoar. This surface hoar layer does not exist in all areas, but has been found on sheltered slopes in the Taylor Fork (video, photo) , Teepee Creek and the Lionhead area (video). Skiers in the Kirkwood Ridge area of southern Madison Range did not find this layer during a tour yesterday. This is a perfect example of how spatially variable surface hoar distribution can be.
If you're out looking for the last scraps of powder today, take a few minutes to dig a snowpit and look for a layer of buried surface hoar sitting 1-2 feet deep. If this layer is present, keep your slope angles below 35 degrees.
Today, avalanches are possible on slopes steeper than 35 degrees which have a MODERATE avalanche danger. Less steeps slopes have a LOW avalanche danger.
Bridger Range Northern Madison Range
Northern Gallatin Range Cooke City
Similar riding conditions will be found in the mountains near Bozeman, Big Sky, and Cooke City. The one component these areas lack is a more widespread layer of buried surface hoar. In a few isolated areas around Big Sky and Hyalite, a layer of small grained facets and/or surface hoar has been found 1-2 feet deep. This layer has a very limited distribution, but should still be looked for and assessed before committing to steeper terrain. Outside of a few lingering problems, the snowpack is generally strong and stable.
Today, human triggered avalanches are unlikely and the avalanche danger is rated LOW.
I will issue the next advisory tomorrow morning at 7:30 a.m. If you have any snowpack or avalanche observations drop us a line at mtavalanche@gmail.com or call us at 587-6984.
AVALANCHE EDUCATION and EVENTS
Take a look at our Education Calendar for all classes being offered.
Snow Science and the Human Factor, Bozeman, MSU Procrastinator Theater, 6-8:00 p.m., Tuesday, February 17. The free event will feature a talk by Powder editor and MSU graduate John Stifter, multimedia presentations on the human factor in avalanche risk, a panel of experts from MSU’s Snow & Avalanche Lab and Gallatin National Forest Avalanche Center, as well as a Q & A session (poster).
Companion Rescue Clinic, Bozeman, REI, 6-8 p.m., Friday, February 20 and 10 a.m.-2 p.m. on Saturday, February 21 (field location TBD). Pre-registration is required: www.rei.com/stores/bozeman.html
1-hour Avalanche Awareness, West Yellowstone, Holiday Inn, 7 p.m., Saturday, February 21.
Companion Rescue Course for Snowmobilers, Cottonwood Drainage, Crazy Mountains, Saturday, February 21, 9:30 a.m. – 2 p.m. Please RSVP to your club officers or to kathrynjbarker@fs.fed.us if you are interested in participating.